Mechanism for firing percussion or time fuses



June 9, 1925. 1,541,279

' L. E. REMCJNDY- MECHANISM FOR FIRING PERCUSSION 03 TIME FUSES Filed Aug. 15, 1924 4 Sheets-Sheet 1 E E" J i-= v a I F F 0 June 9; 1925.

L. E. REMONDY MECHANISM FOR FIRING PERCUSSION OR TIME FUSES Fil d Aug; 15, 1924 4 Sheets-Sheet 2 F AA z. f Elm-Em .5une 9, i925.

Filed Aug, 15 1924 4 Sheets-Sheet 3 v f ii... M 0

Patented June 9, i925.

LEON EMILE BEIVLO'NDY, 0F RUEIL, FRANCE.

ncnnmsn non FIRING rnncu'ssron on min -n rosns.

Application filed August 15, 1924. Serial No. 732,305.

To QZZtlQhOITL it may concern:

Be it known that I, Liion Em lia Rn- MoNpY,acitizen of the Republic of France, residing. at Rueil (Seine et Oise), France, have invented new and useful Improvements in Mechanism for Firing Percussion or Time F uses; which invention is fully set forth in the following specification.

It is known that mostper cussion or time. fuses necessitate an arrangement which prevents any premature operation. of the firing mechanism during transport, under the effect o f an abnormal shook or in case of an accidental. fall of the projectile or the case which holds it. r v

The known devices which act as safe guards against such premature operations have to be capable ofbeing withdrawn before firing, or during firing, while the pro; jectile is in flight, otherwise they would offer resistances to the operation of the fuse, when the projectile meets objects which penetrates easily, of such character as to practically destroy the operation of the fuse. That is, the known sateg'nards it they were not capable of being withdrawn at a. given time, would take all sensitiveness from the fuse. The known safeguards are therefore of a. temporary character and have to be made inoperativ previous to or during the flight. of the projectile. v In certain applications, such as for example the firing of a projectile at a very low speed, by trench mortars, or the throw,- ing of a bomb from air craft, the automatic withdrawal is most generally very ,dil ncult to effect, which necessitates having recourse to a hand operated arrangement, by the drawing out of a pin or any other similari locking device. The disadvanta es of such an arrangement are. obvious: the possibility of forgetting to effect. the release, the possibility of a premature release; apart from the eXt-ernaloperation which has to be performed on the removable member implies a communication with the interior of the mechanism, and necessitates having a joint so tight that its construction would be almost impossible.

This invention relates tow a safety device for percussion or time fuses of the type which are particularly adapted for projec tiles fired at low velocities, butnsuitable nevertheless by reason of its extreme sim For obtaining these important results the at n d v s QQ P i n p i e rl 'body interposed between the str ker. and the-percusslon cap and across which the two members may be brought. into contact with each h h a bad y be is rm lly held a a determined distance from one of the menm bars by a. resilient resistance, while the sec ond member is held by a second resilient resistance at a determined distance both from the separator body and from the first member. These distances of separation ensured normally by the said resilient resistances, the masses of the members, (striker: and percussion cap) and of the separator body, as well as the resilient resistances, are determined so that engagement of the strilrer and the percussion cap across the separator will not bev possible except under conditionswhich are produced practically only during firing, that is to say: a high negative acceleration but of short duration, against an obstacle of high resistance, a weaker gnegativc acceleration but sufii} ciently high and suiiiciently prolonged, in the event of the projectile meeting an obstacle of weak or medium resistance.

Various practical applications and forms of construction of the invention are illustrated by way of example on the accompanying drawings in which:

Figures 1 to 4 show a first example of the application of the invention to a base fuse. Figure 1 is a sectional elevation showing the parts in their normal position of rest. Figure 2 is a similar sectional elevation showing the parts in an intermediate working position.

. Figure 3 is a section showing the parts in the position they occupy at the moment at which the firing takes place following the shock against the resisting obstacle or against an obstacle of weak or average resistance, with a sufficiently high and prolonged negative acceleration.

Figure 4 is a section showing the parts in a position which may result from the meeting of the projectile with an obstacle of high resistance the shock not'be-ing 'acc ompanied by a negative acceleration sufficiently prolonged or of suflicient value for the firing;

illustrating a time device embodying the present invention.

Figs. 10, 11 and 12 are sectional views illustrating another'embodiment of the present invention. I

7 Referring to Figures 1 to a'incl'usive, A is the body'of the fuse in which are arranged the usual members of the firing'mechanism.

In this example, it has been assumed that one of the members, the percussion cap B, is fixed in the body of the fuse, the other member, the striker C is movable.

According to the invention the safety device, preventing any premature operation of the firing mechanism, comprises aseparator body D, provided with a pipe, canal, or passage d, through which the movable member C can come into contact with the'fixed member B. The movable separator D is normally held at a determined distances from the fixed percussion cap or primer "B, by a resilient resistance spring E which is supported at one end on a fixed part, and at the other, against the said separator which latter'is thus pressed against the shoulder a on the body of the fuse. A second resilient resistance, such as the spring F, keeps the mov able member (the striker C) at a distance g from the percussion cap and at the same time at a distance 2' from the body of the separator D. I

I movable members C and of the separator body' D, by suitably choosing relative values of these masses and of the resistances of the springs F and E, and by also suitably choos-- ing the distances w, y, z a fuse comprising an automatic safety device is produced by means of the arrangements shown, which automatic safety device becomes inoperative their inertia upon the resilient resistances F and E respectively. It is essential for the operation of the arrangement according to the invention that the pressure exerted by the separator body D on the resistance E should take place'before the pressure exerted by C on the resistance F ceases. It is seen for example, that in the case of equal relations between the mass C and the resistance F on theone hand, and the mass D and the resistance E on the other hand, it is sufficient to choose a very much less than y so that D may arrive at the end of its path before the point of the striker has been able to come into contact with the percussion cap B. This intermediate position is shown on the Fig ure 2. If at the moment when the parts are in this position the speed ofthe projectile is destroyed the inertia of the mass D ceases to act on the resistance E. At the instant that the resistance E reacts, due to its resiliency, on the separator D, the latter is given a movement of recoil and is moved to theposi tion indicated in Figure 4, where it deadens the movement of the striker towards the percussion cap. In order to accomplish this the mass of the separator body D is made greater than that of the member C since it would be impossible to produce a pressure on D by C unless the kinetic energy (1/2 of mV of C at this moment is very great. The kinetic energy of the mass Cdepends primarily on the factor V which is governed by the speed of the projectile carrying the fuse.

If upon the meeting with an obstacle of low or average resistance the movement of the projectile lasts for a suflicient time, the

pressure of D 'upon the resistance E will itself last for a suflicient time, so that, the positive action of C upon the resistance F exerting itself freely, the striker will come into contact with the percussion cap, the parts in this case occupying the firing posi-' tion indicated on Figure 3. The par-ts will take up this position whatever be the By suitably determining the masses of the 7 conditions of working (kinetic energy of the striker great enough atthe moment of shock, accompanied by a negative acceleration of short duration, a negative acceleration sufficient and prolonged, in case of meeting with an obstacle of weak or averageresisb 'ance).

' If, as it will be seen, the operation of the firing mechanism is assured .under conditions which are normally met with during firing, on the other hand the safety device prevents in an eficienlt manner the said operation under circumstances which may arise inig'eneral in case .of accidents during rolling, transport or handling.

The most frequent accidents are, in fact, among the following 1. A shock from a small height against a resisting obstacle.

In this case, the kinetic energy of the separator D, as well as .that of the striker C, are insufficient to OVQlCOHiQ the resilient resistances E and F respectively; therefore the operation is impossible.

2. A shock from a medium height (e. g. of the order of 10 to 20 metres against a resisting obstacle; such an accident is possible, when loading a vessel). In this case the kinetic energies of D and C are sufficient to determine the compression of the resilient resistances E and F; however, owing to the short duration of the inherent negative acceleration due to the rapid stopping of the projectile against the resistant body D, as soon as it has arrived, at the end of its path undergoes amovement' of recoil, under the action'of the expansion of E, and this before C has completely overcome the resistance of F; and since the kinetic energy of C has, due to the too low speed of the, projectile, insufficient value to overcome the reaction of D, the operation is again impossible. 4

3. Shock-from a medium height (from as much as '50 metres forexample) against an obstacle of low and medium resistance. In this case, the duration of the penetration of the projectile into the obstacle, and accordingly the negative acceleration whlch it undergoes may, it is true, be sufliclently great, but the shock being less violent, that is to say, the negative acceleration of the proj ectile being of less value owing to a slowing down instead of an abrupt stop, the inertia-s of the masses D and C are insuflicient to enable them to complete their paths, so that the operation is once more impossible.

It is to be understood that the three shocks described above include any that would be imposed on the fuse when it is submitted to the well known drop test, and it will be ap parent to those skilled in the art that the fuse is capable of passing other safety tests, as for example, a rolling test.

In the embodiment of the invention illustrated in Figure 5, the separator body 1) and the striker C normally engage the inner surface a of the fuse body. The spring F is placed in'a recess in theseparator D, and one end of the spring presses against the bottom of the recess.

In the nose fuse illustrated in Fig. 6, it has been assumed that the fixed part of the firing mechanism was constituted by the striker B, themovable part .G beingconstir for, aircraft bombs embodying the present invention, the body of. the fuse A is provided with a'tubular extension A of suitable length so thatits end may project above the top of the tail fins G of the projectile. The separator body D is itself extended out'.-

sideof the tubular extension A? of the fuse body, and is normally, that is to saybefore the launching of the bomb, held in position, atthe distance x from the fixed percussion cap 'B, by a holding member such as a grip Hwith resilient arms.

The sepjarator'l)forms by means of a pin d or any other abutment, support for the upper end of the striker C. The fuse has been shown in combination with an arrangement of delay carrier I (which forms the subject of an application for patentfiled on the 5th February 1924 under the Serial No. 690,813).

Upon the launching of the bomb, its fall effects the escape of the separator D from the'arms of the grip H fixedto theair craft. If it is desired. to release aninert bomb, that is to say, without the operation of the firing mechanism, whatever he the height of the fall, the bomb is allowed toescape together with the grip which is released from its attachment to the air craft.

Although the safety ,device described is entirely sufficientin itself, it is to beunderstood that it may .be combined with addi-- tional known safety devices, for example of the type in which the automatic withdrawal is effected under the action ofthe centrifir. gal force during the. flightuof the projectile, or any other in which the withdrawal only takes place at the end of the positive acceleration of the projectile. In this way, as shown in Figure 8, which presents a mod ification of the base. fuse shown in Figure ,5, it is pessibleto provide on the outside surfa e of the separator body D, and place in it the segments J, which are held together,. in the known manner, .by an extensible thread j, the, said segments being held against any longitudinal displacement. by virtue of their'lodging in a hollow A iii the body of the fuse A. I

The'nejw safety device may be applied to time fuses,to ensure in theknown man.- ner' upon the firing of the projectile, the starting of the burning of a fuse composi? tion, the flame of which is transmitted to the charge only after the end of a time which may be varied as desired.

Figure 9 illustrates. in sectional elevation a similar construction. Inv this ex+ ample,the firing mechanism is lodged in an inverted socket A being fixed, by screws. for example, on .thebodyvof the fuse proper A.

The mechanism comprisesas in the preced ing examples a'percussion cap B, a movable striker C, a tubular separator body D a resilient'support E for the separator and a resilient support F for the striker. In the socket A are arranged holes a by means of which the flame is transmitted in the known manner by means of a fuse composition K, having fuse rings or a peripheral edging of powder, for the ignition of the charge at the end of a time: which maybe varied.

It is quite evident that during the rolling, transport or handling, the safety device offers in this examplethe same safeguard as in the case of a percussion fuse. In addition the conditions of speed and of dura tion of acceleration of the projectile during its passage through the barrel of the cannon, are always such that the operation of the mechanism is ensured duringthis passage, seeing moreover that the position of the members is inverted so that the inertia of the separator and that of the striker come into play for this. operation as soon as the projectile is put into motion instead of coming into play, as in the preceding examples, upon meeting an obstacle. In the examples which'havebeen described it'has been assumed that one of the parts of the firing mechanism, striker or percussion cap was fixed in the body of the fuse. In certainv applications, particularly in the case of a projectile released from on board an air craft, it would be advantageous to arrange the fuse in such a manner that its operation is effected whether the projectile falls on its nose or on its base. The new safety device may be employed equally well in this case,it will suffice, as is shown for example in sectional elevations of a nose fuse in the Figures 10, 11 and 12, to make the two mem bers of the mechanism movable.

The separator D is in this casekept floating between the two movable members B and C, on resilient supports E and F.

If equal masses are-chosen for B and C it will be necessary to make Eand Frof the same resistance. V

Figure 10 shows the parts in position of rest; Figure 11 shows the parts in the position they will occupy in the case of a fall at high speed on the head of a projectile; Figure. 12 shows the parts in the position they-will occupy in the case of a fall at high speed upon the base-of the projectile.

lVhile the embodiments of the invention illustrated in the drawings have been de scribed with considerable particularity, it

is to be expressly understood that the in-:

vention is not limited thereto, since the same is capable of being embodied or.carried out in a variety of ways, some of which will now readily suggest themselves to those skilled in the art, while changes may be made in details -of construction and arrangen'ient, without departing from the spirit of the invention. as herein employed includes fused bodies of all types. Reference is therefore to be had to the claims hereto appended for a definition of the limits of the. invention.

. I claim:

1. A fuse for projectiles comprising a body, primer and striker elements'in said body, one of said elements being slidably The term projectile i nounted, a separator slidably mounted between said-elements, and resilient means interposed between the separator and each of said elements.

2. A fuse for projectiles comprising a body, primer and striker elements in said body, a separator slidably mounted between said elements, the mass of said separator being greater than themass of the slidably body, primer and striker elements in said body, one of said elements being situated forwardly of the other of said elements, and means for preventing accidental firing of the fuse, said means including a separator lili'i body, and means for moving said separator body towards normal position to engage the rearwardly situated element and preventthe latter from contacting the forwardly situated element.

5 A fuse for projectiles body, primer and striker elements in said body, one of said elementsbeing situated forwardly of the other of said elements, and means forpreventing accidental firing of the fuse, said means including a separator body, and a spring for moving said separator body into engagement with. the rear wardly situated element to prevent the latter from cont-acting the forwardly situated element. j v

6. A [fuse for projectiles comprising a body, primer and striker elements in said body, one of said elements being situated forwardly ofthe other of said elements, a separator body slidably mounted between said elements and having a mass greater than the mass of the rearwardly situated one I of said elements, and resilient means interposed between said elements.

7'. A- fuse for. projectiles comprising a body, primer and striker elements in said body, one of said elements being situated comprising I a and means including a slidably mounted separator and a spring for yieldingly preventing contact between said elements when the fuse is subjected to a drop test.

9. A fuse for projectiles comprising a body, primer and striker elements in said body, one of said elements being situated i forwardly of the other of said elements, and

one of said elements being slidably mounted, and means including a plurality of longitudinally separated coil springs for yield ingly preventing contact between the elements when the fuse is subjected to a drop test.

10. A fuse for projectiles comprising a body, primer and striker elements in said body, one of said elements being slidably mounted, a separator body interposed between said elements, resilient means for normally maintaining said separator body at a determined distance from one of said elements, and resilient means for normally maintaining the slidably mounted one of said elements at a determined distance greater than said first-named distance from the other of said elements.

11. A fuse for projectiles comprising a body, primer and striker elements in said body, one of said elements being situated forwardly of the other of said elements, a separator body slidably interposed between said elements, resilient means for normally maintaining said separator body at a deter mined distance from the forwardly situated one of said elements, and resilient means for normally maintaining the rearwardly situa-ted element at a determined distance from said forwardly situated element.

12. A device of the class described comprising a fuse body, primer and striker elements in said body. one of said elements being positioned in front of the other, a separator body slidably positioned between said elements, a spring for normally maintaining said separator body at a determined distance from the forwardly situated one of said elements, and a spring for normally maintaining said 'rearwardly situated element at a determined distance from the other of said elements, said last named dis- I tance being greater than the first named distance.

13. A device of the class described eo1nprising a fuse body, primer and striker elements in said body, one of said elements be prevent contactbetween the elements when the device is subjected to a drop test.

14. A device of the class described .comprising a fuse body, primer and striker ele* ments in said body, one of said elements being positioned in front of the other, a mem ber'slidably mounted between said elements, a spring interposed between said member and the rearwardly situated one of said elements, and means interposed between said member and the forwardly situated one of said elements for moving said member into engagement with the rearwardly situated oneof said elements to prevent firing of the device when the latter is subjected to a drop test.

15. A device of the class described comprising a body, a separator member having a longitudinal opening therethrough, primer and striker elements in said body, said striker element extending within said opening, and means interposed between said member and each of said elements for yieldingly preventing engagement of said ele ments when the device is subjected to a drop test.

16. A device of the class described comprising a body, a separator member having a longitudinal opening therethrough, primer and striker elements in said body, said striker element extending within said opening,

and a spring interposed between said member and each of said elements for preventing engagement of said elements when the device is subjected to a drop test. r

17. A device of the classdescribed com prising a body, primer and striker elements in said body, the forwardly situated one of said elements being fixedly secured to the body and the rearwardly situated one of said elements being slidably mounted in the body, a separatorslidably mounted in the body, a spring interposed between the sepa rator and the fixed element, and a spring interposed between the separator and the slidably mounted element.

p 18.. A device of the class described com prising a body, a primer mounted in the body, a striker slidably mounted in the body.

a separator slidably mounted between the striker and primer, a spring interposed between the separator and primer, and a spring interposed between the separator and striker.

Dated this 17th day of July 1924. In testimony whereof I have signed this specification.

LEON EMILE REMQNDY. 

